|Year : 2016 | Volume
| Issue : 1 | Page : 33-36
BMI and breast cancer in upper Egypt
Abeer F Amin
Department of Oncology, Assiut University Hospital, Assiut, Egypt
|Date of Submission||10-Nov-2015|
|Date of Acceptance||11-Jan-2016|
|Date of Web Publication||18-Apr-2016|
Abeer F Amin
Department of Oncology, Assiut University Hospital, Assiut
Source of Support: None, Conflict of Interest: None
Background and aim
BMI may be an important factor affecting breast cancer outcome.
Materials and methods
The present study included 100 patients who were newly diagnosed with breast cancer at Assiut University Hospital. Their BMI was measured, and the relation of BMI to the stage of breast cancer and age was determined.
Patients' ages ranged from 27.0 to 72.0 years. Overall, 45% of the patients were between the ages of 50 and 60 years, and their mean age was 50.6 years. Stage I, II, III, and IV breast cancer were diagnosed in 14, 64, 12, and 10% of the patients, respectively. Around 29% of the patients were overweight and 35% of them were obese. There was a significant positive correlation between age and BMI (P = 0.000). In addition, there was a significant positive relation between BMI and the stage of breast cancer at diagnosis, with a statistical significant difference (P < 0.05).
Overweight and obese breast cancer patients were more often older, and this was significantly associated with later stages at diagnosis.
Keywords: BMI, breast cancer, upper Egypt
|How to cite this article:|
Amin AF. BMI and breast cancer in upper Egypt. Al-Azhar Assiut Med J 2016;14:33-6
| Introduction|| |
BMI is used to define body weight status (normal, overweight, and obese). BMI is calculated as body weight in kilograms divided by the height in meters squared (kg/m 2). For people aged 20 years and older, weight status categories are defined as follows:
Obesity is one of the major public health burdens in the world. The WHO stated that overweight and obesity are the most important of the known avoidable causes of cancer after tobacco consumption . According to a study in the prestigious British medical journal, The Lancet, Egypt is the seventh most overweight country in the world. Obesity may increase incidence of various human cancers, as reported in different epidemiological studies . Breast cancer is the most common and the leading cause of death because of cancer among women worldwide .
Several studies have reported that menopausal women who are overweight or obese have a higher risk for breast cancer [3–5]. Many epidemiological studies have shown evidence suggesting that a higher BMI is positively associated with an increased breast cancer risk in postmenopausal women , but is conversely reduced in premenopausal women ,. Women who are overweight or obese after menopause have a 30–60% higher risk for breast cancer compared with those who are lean .
Obesity increases the risk for cancer by increasing the levels of hormones such as estrogen and insulin ,. In early life, estrogen is mainly produced in woman's ovaries, but after menopause, fat in the body becomes the main source of estrogen, and so obese women have up to twice as much estrogen as women with a healthy weight; in addition, they have lower levels of 'sex hormone binding globulin', which mops up estrogen in the body .
Women who are overweight and obese tend to have higher levels of insulin compared with lean women . Postmenopausal women with high levels of insulin, including women with type 2 diabetes, have shown an increased risk for breast cancer . Any possible link between insulin levels and breast cancer risk are less clear among premenopausal women .
In one large study, women who had lost four to 11 pounds after menopause had more than 20% lower risk for breast cancer compared with women whose weight did not change , but not all studies showed this result .
Treatment outcome and the impact of BMI have been reported in patients with breast cancer receiving endocrine therapy in several studies. These studies demonstrated that the efficacy of aromatase inhibitors vary with BMI but the efficacy of tamoxifen is not BMI-dependent .
| Materials and methods|| |
This prospective, randomized study included 100 newly diagnosed breast cancer patients in Assiut University Hospital between August 2013 and August 2014. Data of all patients were analyzed as regards their age, body height, and weight; BMI was calculated and correlated with the stage of breast cancer and age at diagnosis. We considered a woman postmenopausal if she had experienced a final menstrual period of greater than 12 months and had not undergone hormonal therapy before or during this interval. On the other hand, women were considered premenopausal if they were still menstruating and had not taken any hormone therapy during the 12 months before the reference date.
The relationship of BMI to the stage of breast cancer at diagnosis was evaluated using the χ2-test for frequency tables of BMI by stage of breast cancer. The Pearson correlation test was used to determine any association between BMI and age.
| Results|| |
In total, 100 newly diagnosed breast cancer patients (age range = 27.0–72.0 years) were included in the present study. We classified them into three age groups: women less than 50 years of age (36% of patients); women equal to or greater than 50 but less than 60 years of age (45% of the patients); and those greater than or equal to 60 years of age (19% of the patients). Their mean ± SD age was 50.61 ± 9.87 years [Table 1]. As regards the staging of breast cancer, according to AJCC staging, stage I, II, III, and IV breast cancer were found in 14, 64, 12, and 10% of the patients, respectively ([Figure 1]).
They were classified according to BMI into three groups as follows: normal (36% of the patients), overweight (29% of the patients), and obese (35% of the patients) ([Figure 2] and [Table 2]).
As regards BMI in different age groups, in the group comprising women aged less than 50 years, the incidence of obesity was 22% and the incidence of overweight was 44%; in the group comprising women aged 50 or above but less than 60, the incidence of obesity was 31% and the incidence of overweight was 29%; and in the group comprising women aged greater than or equal to 60 years, the incidence of obesity was 0% and the incidence of overweight was 68%, with a significant P value (P = 0.002*) [Table 3].
Using the χ2-test to compare BMI in different stage groups of breast cancer, there was a significant difference with higher percentage of overweight and obese in fall in late stage group with a statistical significant difference (P < 0.05) [Table 4].
| Discussion|| |
In our study, overweight and obesity were significantly associated with the later stages of breast cancer at diagnosis (III, IV). This may be because of little likelihood of obese women participating in screening ,; in addition, the increased adipose tissue in obese women may affect early breast cancer detection or may have a biological effect on cancer growth .
Obese and overweight women with breast cancer in our study were more often older, with a significant P value (P = 0.002*), which is in agreement with the fact that an excess of adipose tissue in postmenopausal women may elevate the production of endogenous estrogen through the increased activity of enzymes aromatase and 17β-hydroxysteroid dehydrogenase. In addition, a decrease in the sex-hormone-binding globulin, caused by obesity and as a result increased formation of estrone and testosterone may finally promote cellular proliferation and inhibit apoptosis in the breast .
| Conclusion|| |
Overweight and obese patients in the present study were more often older, and this was significantly associated with the later stages of breast cancer at diagnosis.
Therefore, keeping weight gain in check may be an important public health strategy for reducing the risk for breast cancer in postmenopausal woman, which could be encouraged through health education programs on obesity and breast cancer in the future.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Reeves GK, Pirie K, Beral V, Green J, Spencer E, Bull D, Million Women Study Collaboration Cancer incidence and mortality in relation to body mass index in the Million Women Study: cohort study. BMJ 2007; 335 (7630):1134.
Bianchini F, Kaaks R, Vainio H. Overweight, obesity, and cancer risk. The Lancet Oncology 2002; 3:565–574.
Renehan AG, Tyson M, Egger M, Heller RF, Zwahlen MBody-mass index and incidence of cancer: a systematic review and meta-analysis of prospective observational studies. Lancet 2008; 371 (9612):5
Jemal A, Bray F, Center MMA. Global cancer statistics. CA Cancer J Clin 2011; 61:69–90.
Renehan AG, Soerjomataram I, Leitzmann MF. Interpreting the epidemiological evidence linking obesity and cancer: a framework for population-attributable risk estimations in Europe. Eur J Cancer 2010; 46 (14):2581–2592.
Lahmann PH, Hoffmann K, Allen N, van Gils CH, Khaw KT, Tehard B, et al
. Body size and breast cancer risk: findings from the European Prospective Investigation into Cancer And Nutrition (EPIC). Int J Cancer 2004; 111 (5):762–771.
Kawai M, Minami Y, Kuriyama S, Kakizaki M, Kakugawa Y, Nishino Y, et al
. Adiposity, adult weight change and breast cancer risk in postmenopausal Japanese women: the Miyagi Cohort Study. Br J Cancer 2010; 103 (9):1443–1447.
Michels KB, Terry KL, Willett WC. Longitudinal study on the role of body size in premenopausal breast cancer. Arch Intern Med 2006; 166 (21):2395–2402.
Tehard B, Clavel-Chapelon F
Several anthropometric measurements and breast cancer risk: results of the E3N cohort study. Int J Obes (Lond) 2006; 30 (1):156–163.
De Pergola G, Silvestris F. Obesity as a major risk factor for cancer. J Obes 2013; 2013:291546.
Louie SM, Roberts LS, Nomura DK. Mechanisms linking obesity and cancer. Biochim Biophys Acta 2013; 1831:1499–1508.
Key TJ, Appleby PN, Reeves GK, Roddam A, Dorgan JF, Longcope C, et al
., Endogenous Hormones Breast Cancer Collaborative Group. Body mass index, serum sex hormones, and breast cancer risk in postmenopausal women. J Natl Cancer Inst 2003; 95 (16):1218–1226.
Hvidtfeldt UA, Gunter MJ, Lange T, Chlebowski RT, Lane D, Farhat GN, et al
. Quantifying mediating effects of endogenous estrogen and insulin in the relation between obesity, alcohol consumption, and breast cancer. Cancer Epidemiol Biomarkers Prev 2012; 21 (7):1203-1212.
De Bruijn KM, Arends LR, Hansen BE, Leeflang S, Ruiter R, van Eijck CH Systematic review and meta-analysis of the association between diabetes mellitus and incidence and mortality in breast and colorectal cancer. Br J Surg 2013; 100 (11):1421-1429.
Eliassen AH, Tworoger SS, Mantzoros CS, Pollak MN, Hankinson SE Circulating insulin and c-peptide levels and risk of breast cancer among predominately premenopausal women. Cancer Epidemiol Biomarkers Prev 2007; 16 (1):161-164.
Eliassen AH, Colditz GA, Rosner B, Willett WC, Hankinson SE Adult weight change and risk of postmenopausal breast cancer. JAMA 2006; 296 (2):193-201.
Teras LR, Goodman M, Patel AV, Diver WR, Flanders WD, Feigelson HS Weight loss and postmenopausal breast cancer in a prospective cohort of overweight and obese US women. Cancer Causes Control 2011; 22 (4):573-579.
Sestak I, Distler W, Forbes JF, Dowsett M, Howell A, Cuzick J Effect of body mass index on recurrences in tamoxifen and anastrozole treated women: an exploratory analysis from the ATAC trial. J Clin Oncol 2010; 28 (21):3411–3415.
Cohen SS, Palmieri RT, Nyante SJ, Koralek DO, Kim S, Bradshaw P, Olshan AF Obesity and screening for breast, cervical, and colorectal cancer in women: a review. Cancer 2008; 112 (9):1892-1904.
Zhu K, Wu H, Jatoi I, Potter J, Shriver C Body mass index and use of mammography screening in the United States. Prev Med 2006; 42 (5):381-385.
Calle EE, Kaaks R. Overweight, obesity and cancer: epidemiological evidence and proposed mechanisms. Nat Rev Cancer 2004; 4 (8):579–591.
[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4]